Commercial simulators, such as flight simulators, are relatively large systems that require a substantial amount of space. A flight simulator, for example, may include a large dome on which imagery is projected. The flight simulator may also include multiple projectors and image generators, which are costly, require a substantial amount of power, and generate a substantial amount of heat, which in turn increases environmental cooling requirements.
On the other hand, simulators that utilize virtual reality (VR) headgear suffer a number of problems that detract from realism. For example, movements of the participant or other objects that would naturally be seen by the participant in a non-VR simulation, such as movement of a cockpit control by the participant's hand, are often not depicted in the imagery even though during such movement the user's hand would come within the field-of-view of the participant if the participant were not wearing the VR headgear. Accordingly, there is a need for a simulator system that also allows a user to simultaneously view real-world foreground objects against virtual background images as a composite scene, such as an augmented reality system.
Chroma key compositing is one method for creating a composite image or scene, but it is not well suited for use in a simulation environment using an augmented reality system that overlays real-world imagery in a live scene with virtual imagery. With conventional chroma key compositing, a foreground image containing one or more objects has a background portion of a predetermined color (typically a saturated shade of blue or green). A processing device removes the monochrome portion from the foreground image and replaces the monochrome portion with a corresponding portion of a second, background image. The objects in the foreground that do not contain the predetermined color are retained, making the foreground objects appear to be in front of the background image, thereby forming a composite image of the foreground objects against a different background. However, in an augmented reality system using a see-through lens, the part of the augmented scene is a real-world environment, such as a vehicle interior, being viewed through a lens of the augmented reality system. For chroma key to function, a portion of the real-world environment, such as a window region of the vehicle interior, must be covered with a bright monochrome surface. When the augmented reality system provides a virtual image corresponding to the monochrome portion of the scene to the user via the lens, however, the monochrome portion of the live scene will still be visible to the user through the lens, because the bright background tends to bleed through the virtual image displayed on the lens, thereby causing the virtual image to appear washed out, faded, and artificial.